Conventional fuel rails for fuel-injected internal combustion engines comprise sockets which are spaced apart along the fuel rail's length and into which the fuel injectors are inserted. The fuel injectors are retained in fluid-tight relation to the fuel rail by suitable sealing and retention means. The typical fuel injector has an elongated shape and is customarily arranged on the fuel rail such that the long dimension of the injector is transverse to the long dimension of the fuel rail. As a consequence of this arrangement, the envelope that is occupied by the fuel rail assembly in the engine compartment of an automotive vehicle will have an extent transverse to the fuel rail that is determined by the long dimension of the fuel injector. Accordingly, a reduction in the extent to which a fuel injector projects transversely of the fuel rail will be beneficial in reducing the envelope occupied by the fuel rail assembly, and this benefit will accrue to the advantage of automotive vehicle designers insofar as styling and packaging considerations are concerned.
One of the several aspects of the present invention relates to a valve useful in a fuel injector for allowing certain reductions in the size of the envelope that is occupied by the fuel rail assembly on an internal combustion engine, particularly reductions in the extent to which the fuel injectors project transversely of the fuel rail. The fuel rail may comprise a circular cylindrical-walled tube within which the fuel injectors are essentially entirely disposed so that the transverse dimension of the fuel rail assembly at the location of a fuel injector is essentially that of the O.D. of the tube. The fuel injectors are mounted on a carrier to form a sub-assembly that is assembled into the tube by endwise insertion. The electrical leads for the fuel injectors run along the carrier to a receptacle that is at one lengthwise end of the completed fuel rail assembly. The injectors' tip ends from which liquid fuel is injected are seated in a sealed manner in holes in the sidewall of the tube. The referenced patent applications disclose details of the carrier and the manner of assembling it into the fuel rail tube.
A valve according to the present invention comprises a rolling ball, or sphere, that is acted upon by the combination of a resilient lever means and a resilient means. The sphere is disposed in a frustoconical-shaped valve seat having an outlet orifice at its base. The resilient lever means resiliently urges the sphere along the axis of the frustoconical valve seat toward concentrically seating on the valve seat thereby closing the outlet orifice. The resilient means acts on the sphere in a sense urging the sphere toward eccentricity with the seat's axis. The relative resiliencies of the resilient lever means and the resilient means are selected such that the sphere normally assumes a condition of concentricity with the seat's axis. An electrical actuator is operatively coupled with the resilient lever means to cause the resilient lever means to selectively operate to a valve closed condition wherein the resiliencies of the resilient lever means and the resilient means are allowed to be effective on the sphere such that the sphere is caused to assume concentricity with the seat's axis thereby closing the outlet orifice and to a valve open condition wherein the two resiliencies are allowed to be effective on the sphere such that the sphere is caused to assume eccentricity with the seat's axis thereby opening the outlet orifice. The valve of the invention is well-suited for miniaturization to fit within a fuel rail and is an efficient and economical use of parts and materials.
Another inventive feature relates to the ability to use a piezoelectric device as the electrical actuator due to the amplification of the device's stroke that is available with a lever means. Differential thermal expansion difficulties can also be avoided by making the piezoelectric device from ceramic elements and making the valve body structure from a ceramic material whose thermal coefficient of expansion is like that of the piezoelectric device.
Further features, advantages, and benefits of the invention, along with those already mentioned, will be seen in the ensuing description and claims, which are accompanied by drawings. The drawings disclose a presently preferred embodiment of the invention according to the best mode contemplated at the present time in carrying out the invention.